#include <bits/stdc++.h>
using namespace std;
#pragma GCC target("avx2")
#pragma GCC optimize("Ofast")
//#pragma comment(linker, "/stack:200000000")
#pragma GCC target( "sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native" )
#pragma GCC optimize("unroll-loops")
/*
#pragma GCC optimize("profile-values,profile-reorder-functions,tracer")
#pragma GCC optimize("vpt")
#pragma GCC optimize("rename-registers")
#pragma GCC optimize("move-loop-invariants")
#pragma GCC optimize("unswitch-loops")
#pragma GCC optimize("function-sections")
#pragma GCC optimize("data-sections")
#pragma GCC optimize("branch-target-load-optimize")
#pragma GCC optimize("branch-target-load-optimize2")
#pragma GCC optimize("btr-bb-exclusive")
#pragma GCC optimize("inline")
#pragma GCC optimize("-fgcse")
#pragma GCC optimize("-fgcse-lm")
#pragma GCC optimize("-fipa-sra")
#pragma GCC optimize("-ftree-pre")
#pragma GCC optimize("-ftree-vrp")
#pragma GCC optimize("-fpeephole2")
#pragma GCC optimize("-ffast-math")
#pragma GCC optimize("-fsched-spec")
#pragma GCC optimize("-falign-jumps")
#pragma GCC optimize("-falign-loops")
#pragma GCC optimize("-falign-labels")
#pragma GCC optimize("-fdevirtualize")
#pragma GCC optimize("-fcaller-saves")
#pragma GCC optimize("-fcrossjumping")
#pragma GCC optimize("-fthread-jumps")
#pragma GCC optimize("-freorder-blocks")
#pragma GCC optimize("-fschedule-insns")
#pragma GCC optimize("inline-functions")
#pragma GCC optimize("-ftree-tail-merge")
#pragma GCC optimize("-fschedule-insns2")
#pragma GCC optimize("-fstrict-aliasing")
#pragma GCC optimize("-falign-functions")
#pragma GCC optimize("-fcse-follow-jumps")
#pragma GCC optimize("-fsched-interblock")
#pragma GCC optimize("-fpartial-inlining")
#pragma GCC optimize("no-stack-protector")
#pragma GCC optimize("-freorder-functions")
#pragma GCC optimize("-findirect-inlining")
#pragma GCC optimize("-fhoist-adjacent-loads")
#pragma GCC optimize("-frerun-cse-after-loop")
#pragma GCC optimize("inline-small-functions")
#pragma GCC optimize("-finline-small-functions")
#pragma GCC optimize("-ftree-switch-conversion")
#pragma GCC optimize("-foptimize-sibling-calls")
#pragma GCC optimize("-fexpensive-optimizations")
#pragma GCC optimize("inline-functions-called-once")
#pragma GCC optimize("-fdelete-null-pointer-checks")
*/
#define ll long long
#define all(x) x.begin(),x.end()
#define sz(x) (int) x.size()
#define f first
#define s second
#define ld long double
#define yes cout << "YES" << endl
#define no cout << "NO" << endl
#define pb push_back
#define dauzhan gay
#define popcount __builtin_popcount
const long double Eps = 1e-12;
const int max1 = 1e9 + 100;
const int min1 = -1e9 *1.4;
const ll mod1 = 1000000007;
const ll mod2 = 2000000011;
const ll mod3 = 3000000017;
const ll mod = 998244353;
const int N = 2e5 + 100;
const int B = 9000000 + 1;
const ll INF = 1e18 + 100;
//mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
ll binpow(ll x,ll y,ll md) {
if(y < 0) return 0;
if(y == 0) return 1;
if(y == 1) return x;
if(y % 2 == 0) {
ll now = binpow(x,y/2,md);
return (1ll*now*now) % md;
}
else {
ll now = binpow(x,y/2,md);
return (1ll*((1ll*now*now) % md)*x) % md;
}
}
/*
for(int i = 1;i <= n;i++) sp[0][i] = a[i];
for(int i = 1;i <= log2(n);i++) {
for(int l = 1;l <= n;l++) {
int r = l + (1 << i) - 1;
if(r > n) break;
int middle = l + (1 << (i - 1));
sp[i][l] = max(sp[i - 1][l],sp[i - 1][middle]);
}
}
int get(int l,int r) {
int g = log2(r - l + 1);
return max(sp[g][l],sp[g][r - (1 << g) + 1]);
}
*/
signed main() {
ios_base::sync_with_stdio(NULL);
cin.tie(0);
cout.tie(0);
int n,m;
cin >> n >> m;
char a[n + 1][m + 1];
bool was[n + 1][m + 1];
bool check[n + 1][m + 1][2];
for(int i = 1;i <= n;i++) {
for(int j = 1;j <= m;j++) {
cin >> a[i][j];
was[i][j] = false;
check[i][j][0] = false;
check[i][j][1] = false;
}
}
int ans = 0;
for(int i = 1;i <= n + m;i++) {
if(i == m + 1) continue;
vector <pair <int,int> > v;
if(i <= m) {
int x = 1,y = i;
while(x >= 1&&x <= n&&y >= 1&&y <= m) {
v.pb({x,y});
x++;
y--;
}
}
else {
int x = i - m,y = m;
while(x >= 1&&x <= n&&y >= 1&&y <= m) {
v.pb({x,y});
x++;
y--;
}
}
v.pb({1,1});
reverse(all(v));
int len = sz(v) - 1;
int dp[len + 2][3];
for(int i = 0;i <= len + 1;i++) {
for(int j = 0;j < 3;j++) {
dp[i][j] = min1;
}
}
dp[1][0] = 0;
for(int i = 1;i <= len;i++) {
for(int j = 0;j < 3;j++) {
if(j != 0) dp[i + 1][j - 1] = max(dp[i + 1][j - 1],dp[i][j]);
dp[i + 1][0] = max(dp[i + 1][0],dp[i][0]);
int nowx = v[i].f,nowy = v[i].s;
if(a[nowx][nowy] != 'W') continue;
if(nowx > 2&&a[nowx - 1][nowy] == 'G'&&a[nowx - 2][nowy] == 'R') {
dp[i + 1][2] = max(dp[i + 1][2],dp[i][j] + 1);
}
if(j == 0) {
if(nowy > 2&&a[nowx][nowy - 1] == 'G'&&a[nowx][nowy - 2] == 'R') {
dp[i + 1][0] = max(dp[i + 1][0],dp[i][j] + 1);
}
}
}
}
ans+=max({dp[len + 1][0],dp[len + 1][1],dp[len + 1][2]});
//cout << dp[len + 1][0] << endl;
}
cout << ans << endl;
}
